The summer comes and Southampton’s best players go. Maybe that annual looting from the Premier League’s A-list explains why Ronald Koeman’s latest creation took so much pleasure in slapping down Chelsea’s B-team on Thursday night.

This was thoroughly one-sided, a potentially tricky Europa League fixture that turned into a stroll on a sunny evening.

For that, Koeman should be broadly grateful to Graziano Pelle, Dusan Tadic and Shane Long for the goals that gave Southampton a first European win since 1981. Beyond that, they should be thankful that no-one has yet stolen Sadio Mane from their squad.

Dusan Tadic (left) sent Vitesse's keeper Eloy Room the wrong way to score the second from the penalty spot

Tadic leaps into the air having scored the second for the Saints just on the stroke of half-time

The Senegalese forward was the shining light in a game where Southampton gave debuts to Marten Stekelenburg, Cedric Soares, Jordy Clasie and Juanmi, while Vitesse had two Chelsea youngsters in their side. None was as effective as Mane, who made two goals and frequently left the competent players of Vitesse looking anything but.

It leaves Southampton needing to avoid a hefty defeat in Holland next week if they are to progress to the final Europa League play-off. Time will tell if success is a burden they could do without.

But, at the very least, Koeman appears to have built a robust side with enough tricks to again be a nuisance in the domestic campaign. They certainly had more than Vitesse could handle.

Southampton striker Shane Long (left) headed in a late third for the Saints as they cruised to victory

Long cheers in celebration after heading in after 84 minutes to round off a comprehensive win

Even with a little goading from Koeman, Vitesse were not quite the handful they might have been. The Dutchman used his press briefing on the eve of the game to suggest the club that gave him his break in management had lost a little of their ‘feeling’, a reference perhaps to their modern status as a Chelsea finishing school.

To that end, Vitesse fielded both Lewis Baker and Isaiah Brown and had a third Chelsea loanee on the bench in Danilo Pantic. Together, they had no effective way of coping with a Southampton squad not long rebuilt from its latest summer pillaging.

The three new starting faces were sturdy enough, but it was one of last summer’s intake – Mane – who made the difference. At times, he was simply brilliant, a twisting and turning irritant that drove Vitesse to the rough stuff. Even that didn’t work.

He made the first with an excellent throughball after 36 minutes, splitting the Vitesse backline and opening a path for Pelle. The striker’s shot into the top corner, taken while heading away from goal, was delightful.

Tadic added a second shortly before half-time, but again it was Mane who supplied the magic. With a swivel he got past Kelvin Leerdam and was then crudely barged off the pitch by Rochdi Achenteh. Tadic sent Eloy Room one way and the ball the other with his penalty.

It was 70 minutes before Stekelenburg had anything to do. When Danilo Pantic had a sight of goal, he made the save. Easy work for him, a good night for his club, which got better when Long had a shot blocked and Juanmi rounded Eloy Room. He crossed for Long, who headed the third. A conclusive win and performance all round.